1. Technical Field
The inventive concept relates generally to image sensors. More particularly, the inventive concept relates to pixels of image sensors including vertical transfer gates.
2. Description of the Related Art
An image sensor is a semiconductor device that converts a photo image (e.g., light reflected by the subject) into an electric signal and thus is widely used in portable electronic devices, such as digital cameras, cellular phones, etc. Generally, image sensors may be classified as charged coupled device (CCD) image sensors and complementary metal oxide semiconductor (CMOS) image sensors. Recently, a backside illumination (BSI) image sensor that receives incident light on its back surface has been developed to improve light reception efficiency and light sensitivity of the image sensor.